Marina's version of the classic cold process soapmaking method (CP)
Please notice these suggestions are made available as general information only. Soap making from scratch implies working with dangerous substances, such as caustic soda in its pure form (NaOH - sodium hydroxide, or KOH - potassium hydroxide). We do not assume or accept any responsibility for, and will not be liable for the accuracy or inappropriate application of any information whatsoever in any material on this website.
If you prefer to avoid working with strong lye solutions, you can choose the easy road and purchase a natural soap base for hand milling, also known as rebatching or, less appropriately, as remilling.
I am placing this set of instructions on my Website basically because it has become difficult to obtain on the Internet reliable information about the basic cold process (CP) method of soapmaking. While there is nothing new in the general concept, I have attempted to describe the process in a way that even beginner soapmakers can understand.
It is however important to note that soapmaking is not suitable for everyone and all. Safety considerations are paramount when working with "lye", and we assume the reader is 100% aware of the risks, and can take total responsibility for the consequences.
Before attempting to make soap for the first time, you might like to check out some basic safety considerations for a run down of the precautions required when working with strong alkalis. For further and general background information about soap and soapmaking, please refer to my soap methods overview and my versions of hot process soap and discounted water cold process methods.
What is CP soap making?
In short, CP (cold process) method is a way to make soap without applying any extra heat. By definition, it is impossible to make really "cold" soap. This is because soap is the product of a chemical reaction (called "saponification") where fatty acids, combined with an alkali, give a salt (=soap) as the final product. You probably remember from your school days that this type of chemical reaction is
exothermic - in other words, it creates heat.
It should be noted however that for saponification to occur, oils, fats and the alkali must all be in liquid form. For this reason, water is needed to dilute the alkali, and oils or fats that are solid at room temperature must first be placed on a heat source to melt.
The alkalis used for soap making are sodium hydroxide (chemical formula: NaOH), and potassium hydroxide (chemical formula: KOH). In their pure form, both NaOH and KOH are solid (powder or flakes). When we talk of "alkali", we refer to sodium or potassium hydroxide, in general. When we talk of "caustic soda", we usually refer to the same thing - whereas a "caustic solution" or "lye solution" is the strongly alkaline liquid made by dissolving pure NaOH or KOH in water.
In case you're wondering, there is no way for making soap, and even less natural glycerine soap, without an alkali. For the fatty acids (fats and oils) to turn into soap, caustic soda must be used - no alkali, no chemical reaction, no salt and no soap. However, properly made natural soap contains some extra fatty acids (which are very good for your skin), plenty of natural glycerine (which, too, is good for your skin), and no free alkali - which is quite the opposite to what happens with factory soaps... even the mildest!
There is no general agreement as to which is the optimal "starting" temperature for a successful batch of soap. The suggestions that follow come from my personal experience and observations, but I am not setting any "laws". Different soapers have different opinions, and I respect them all.
Double check and make notes!
Saponification calculators, pen and paper are a soaper's best friends. Whichever the source of your recipe, always run the amounts through a SAP calculator and make sure the amount of caustic soda is within the safety threshold (from 3% to 10% superfatting, 0% superfatting for laundry and cleaning soaps only).
Also.... don't forget to make notes. Troubleshooting a problem batch is impossible, unless we know exactly what we did, how we did it and in which order. No notes also mean replicating a successful batch might be very difficult. So don't be afraid... and write :-)